Editorial Open Heart: first published as 10.1136/openhrt-2014-000173 on 19 October 2014. Downloaded from Lorcaserin for the treatment of obesity? A closer look at its side effects James J DiNicolantonio,1 Subhankar Chatterjee,2 James H O’Keefe,1 Pascal Meier3,4 To cite: DiNicolantonio JJ, fi Obesity is developing into a pandemic in higher af nity for 5-HT2C than for 5-HT2A ’ – Chatterjee S, O Keefe JH, countries like the USA, the UK and India.1 3 receptors and 100 times higher selectivity for et al. Lorcaserin for the 13–15 treatment of obesity? A The WHO projects that by 2015, about 700 5-HT2C than for the 5-HT2B receptors. 4 closer look at its side effects. million adults will be clinically obese. It has achieved a clinically meaningful weight Open Heart 2014;1:e000173. Obesity is a major public health problem, loss as per Food and Drug Administration’s doi:10.1136/openhrt-2014- beyond the disability directly related to exces- (FDA’s) guidance criteria (2007), that is, 000173 sive adiposity, and it also increases the risk of a mean efficacy criterion (a medication- several chronic diseases such as hyperten- associated (ie, greater than placebo) weight sion, sleep apnoea, diabetes, coronary artery reduction of 5%) and a categorical efficacy fi Accepted 1 October 2014 disease and cancer. Clearly, obesity is a criterion (a signi cantly greater proportion serious threat, imposing a vast economic (at least 35%) of those individuals receiving burden on the healthcare system.5 the medication compared with placebo con- Obesity is the second most common pre- trols maintaining a 5% weight loss from their ventable cause of death, second only to initial weight).16 Lorcaserin is indicated as an tobacco use.6 Evidence suggests that weight adjunct to a reduced-calorie diet and reduction substantially lowers the risk of increased physical activity for the chronic related comorbidities and fosters their thera- weight management in adults with an initial peutic management.78Although bariatric BMI of 30 kg/m2 or greater (obese) or surgery has emerged as the most clinically 27 kg/m2 or greater (overweight) in the pres- effective strategy for decreasing body weight ence of at least one weight-related comorbid for people with morbid obesity (body mass condition (ie, hypertension, dyslipidemia, http://openheart.bmj.com/ index (BMI) ≥40) or for those who cannot type 2 diabetes).17 be managed otherwise,9 it is a very invasive With one-third of the adults living in the procedure with significant risks.10 11 At this USA considered to be overweight and more juncture, behavioural therapy, lifestyle modi- than a third obese, a potentially huge market fication and pharmacotherapy remain the exists for lorcaserin.18 Thus, it is important mainstays of treatment. The most appealing to understand lorcaserin’s side effect profile solution for the public in general would be a and its risk-to-benefit ratio. Despite the fact ‘weight loss pill’. Several drugs have been that the lorcaserin package insert states that tested since the 1960s, such as thyroid it does not cause a significant increase in on September 27, 2021 by guest. Protected copyright. hormone, dinitrophenol, various forms of FDA-defined valvulopathy, defined as mitral amphetamines, aminorex, fenfluramine, phe- regurgitation greater than mild or aortic nylpropanolamine, rimonabant, orlistat and regurgitation greater than trace (pooled rela- 1 sibutramine. All but phentermine, phendi- tive risk (RR) of the phase 3 echocardio- Mid America Heart Institute 17 at Saint Luke’s Hospital, metrazine and orlistat have been banned graphic data: 1.16; 95% CI 0.81 to 1.67), a Kansas City, Missouri, USA because of serious side effects. Aminorex was look at the FDA Medical Review states that 2R.G. Kar Medical College & introduced in 1965 in Switzerland and was lorcaserin causes a significant increase in Hospital, Kolkata, found to cause pulmonary hypertension. moderate or greater mitral regurgitation at West Bengal, India 3The Heart Hospital, Lorcaserin (ADP356; Trade name: Belviq week 52 (RR 1.95; 95% CI 1.05 to 3.59, p University College London marketed by Arena Pharmaceuticals) and value not stated) and (RR 1.88; 95% CI 1.02 Hospitals, London, UK topiramate/phentermine (Qsymia) are the to 3.47, p=0.04) based on our forest plot) 4Yale Medical School, New most recent additions to the armamentarium (figure 1).19 These data were based on a Haven, Connecticut, USA of antiobesity medications.12 meta-analysis of three randomised controlled Correspondence to Lorcaserin is a novel drug acting selectively trials testing lorcaserin 10 mg twice daily Dr James J DiNicolantonio; as a 5-HT2C receptor agonist in the hypothal- versus placebo. Moreover, the upper bound [email protected] amus with a functional selectivity of 15 times of the 95% CI (1.67) exceeded the 1.5 upper DiNicolantonio JJ, Chatterjee S, O’Keefe JH, et al. Open Heart 2014;1:e000173. doi:10.1136/openhrt-2014-000173 1 Open Heart Open Heart: first published as 10.1136/openhrt-2014-000173 on 19 October 2014. Downloaded from Figure 1 Relative risk of moderate or greater mitral regurgitation at week 52. bound requested by the FDA to rule out an excess risk (secondary to the chronic left ventricular volume of valvular heart disease with lorcaserin. More data are overload). certainly required to ascertain lorcaserin’s risk of valvulo- Of equal concern is the finding that lorcaserin seems pathy,20 as mitral regurgitation was consistently increased to be associated with an increased incidence of depres- in the lorcaserin arm.19 In regard to the question if sion (OR 1.89; 95% CI1.04 to 3.44, p=0.04) (figure 2) weight loss impacted mitral regurgitation, the lorcaserin based on a pooled analysis of the same three rando- FDA Medical Review specifically states, “mean weight mised controlled trials testing lorcaserin 10 mg twice loss in patients without FDA-defined valvular heart daily versus placebo. In BLOOM-diabetes mellitus (DM), disease was 4.7 kg, mean weight loss in patients with there was also an increase in adverse events related to FDA-defined valvular heart disease at week 52 was ischaemic heart disease with lorcaserin versus placebo 6.3 kg. However, when three FDA-defined valvular heart (0.6% vs 0.4%, respectively) with a twofold increased disease outliers are removed, the mean change—and dif- rate of cardiovascular death, non-fatal myocardial infarc- ference between groups—is attenuated (mean weight tion or non-fatal stroke.19 Lastly, there may be an loss in patients with FDA-defined valvular heart disease increase in ‘possible’ primary pulmonary hypertension (VHD) is 5.2 kg) suggest that weight loss per se does not with lorcaserin. Indeed, data derived from a pooled ana- fully explain the difference in VHD between groups” lysis of both BLOOM and BLOSSOM (n=3470), using a (pages 73 and 74 of the FDA medical review).19As for 35 mm Hg or greater increase in systolic arterial pul- any 5HT receptor agonist, lorcaserin may similarly act to monary pressure as a cut-off for ‘possible’ primary pul- cause valvular fibrosis and subsequent mitral regurgita- monary hypertension, yield an increased risk with tion. It acts via the 5HT2B receptor widely expressed on lorcaserin versus placebo (OR 1.41; 95% CI 0.87 to 2.27, valvular leaflets and pulmonary arteries. On activation of p=0.16).19 Although not a statistically significant finding, β the 5HT2B receptor, phospholipase C- is activated, primary pulmonary hypertension is a very serious clin- which further activates protein kinase C (PKC). It also ical adverse effect with a high mortality rate, and thus http://openheart.bmj.com/ phosphorylates Src and thus activates extracellular- any possibility of an increased risk should be taken regulated kinase 1(ERK1) and ERK2. ERK1 and ERK2 seriously. can also be activated by PKC itself. Along with this, 5HT The side effects of lorcaserin, related to valvulopathy itself and Src activate tissue growth factor β receptor 1 (mitral regurgitation), possible increased systolic arterial (TGFβR1) leading to phosphorylation of SMAD-2 and pulmonary hypertension and depression, and possible SMAD-3 and formation of a complex with SMAD-4. This increases in the risk of cardiovascular events would not complex ultimately translocates to the nucleus to activate be gleaned from a close reading of the package insert. As specific genes leading to the proliferation of valvular millions of people are overweight or obese, it is important interstitial cells, secretion of increased glycosaminogly- to understand the side effects of lorcaserin before the on September 27, 2021 by guest. Protected copyright. cans (probably through the upregulation of 5HT2BR widespread use of this medication occurs. Moreover, the and downregulation of the 5HTT gene). This series of effect size of lorcaserin’s 3.3% weight reduction (the events ultimately results in a thickening of the valve with mean placebo-subtracted weight loss at week 52 with lor- glycosaminoglycans (GAG)-rich fibromyxoid tissues, dis- caserin 10 mg twice daily from baseline from the pooled organisation of collagen fibres and neovascularisation efficacy analysis)19 appears trivial in the context of these leading to valvular regurgitation.21 The incidence of potential side effects. Large randomised controlled trials mitral regurgitation associated with lorcaserin does not are urgently required to fully elucidate the risk to benefit seem to be explained by the reduced left ventricular the profile of lorcaserin. Moving forward, a further assess- ejection fraction. Rather, the reduced left ventricular ment of mitral regurgitation or reanalysis of the available ejection fraction may occur due to mitral regurgitation echocardiograms by an independent core laboratory Figure 2 OR of depression. 2 DiNicolantonio JJ, Chatterjee S, O’Keefe JH, et al.